Charging of preheated coal into the coking chambers of a coke oven battery



3,523,965 HAMBERS L. D. SCHMIDT Aug. 4, 1970 CHARGING OF PREHEATED COALINTO THE COKING C OF A COKE V@VEN BATTERY 5 Sheets-Sheet l OriginalF'iled July 20, 1964 INVENTOR. Aw/('f/vce 52W/w07:

L. D. scHMlDT 3,523,065

COAL INTO THE COKING CHAMBERS Aug. 4, 197( 9 CIARGING OF PREHEATED OF ACOKE OVEN BATTERY 3 Sheets-Sheet Original Filed July 20, 1964 Aug. 4,1970 D. SCHMIDT 3,523,955

CHARGING OF PREHEATED COAL INTO THE COKING CHAMBERS OF A COKE OVENBATTERY Original Filed July 20, 1964 3 Sheets-Sheet 3 United StatesPatent O 3,523,065 CHARGING OF PREHEATED COAL INTO THE COKING CHAMBERS FA COKE OVEN BATTERY Lawrence D. Schmidt, New York, N.Y., assignor toAllied Chemical Corporation, New York, N.Y., a corporation of New YorkOriginal application July 20, 1964, Ser. No. 383,750. Divided and thisapplication Jan. 14, 1969, Ser. No. 810,061

Int. Cl. C10b 31/04 U.S. Cl. 201-40 2 Claims ABSTRACT OF THE DISCLOSUREA method of charging the coking chambers of a coke oven battery equippedwith a larry car having charging hoppers, each of which are providedwith drop sleeves for communication with respective charging holes ineach coking chamber of the battery. Coarsely comminuted coal particlesare preheated to a temperature within the range of from 250 to 700 F.and fed into the charging hoppers of the larry in an amount equal to adesired charge for a coking chamber. The larry is then moved intoposition to charge a coking chamber whereupon the preheated coal fromthe charging hoppers is discharged through the drop sleeves into thecoking chamber at a rate to produce the desired charge within saidcoking chamber in not less than about minutes, while a carrier gas fromthe group consisting of steam and coke oven gas is introduced into thedrop sleeves to prevent aspiration of air into the coal streams fallingthrough said drop sleeves into the coking chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a divisionof application Ser. No. 383,750, filed July 20, 1964.

The advantages of introducing coal preheated to a temperature within therange of from 250 to 700 F. so that the coal is dry and below thetemperature at which the coal is in a plastic state, necessary to permitintroduction of the preheated coal into the coking chambers, has beenrecognized. Paramount among these advantages is the reduction of cokingtimes within the coking chambers, with consequent marked increase in thecapacity of the battery for this reason and also because the charging ofdry coal enables the charging of more coal per unit volume of the cokingchamber. When coal containing moisture is introduced into the cokingchambers the amount of heat required to be transferred through the wallsof each chamber to and through the stationary charge to evaporate thewater content of the charge is indeed large. About 40% of the totalcoking time is spent, in prior conventional coking practice, to effectthe necessary heat input throughout the charge to evaporate and removethe water content of the charge and to raise the temperature thereof towithin the range of from 250 to 700 F. In modern practice, with largecoking chambers having a capacity, say, of about 15 to 25 tons perchamber, the coking time is usually from about 15 to 30 hours dependingon the type of the coke produced, namely, whether blast furnace coke orfoundry coke. A saving of 40% of this time is indeed of vast economicimportance. The charging of preheated coal also improves the quality ofthe coke, especially in the case of coals of higher oxygen content, suchas Illinois coals.

It has been proposed to preheat the coal in a luidized state in auidizing and heating chamber externally of the coking chambers of thebattery to a temperature of 3,523,065 Patented Aug. 4, 1970 about 700 F.and then convey the preheated tluidized coal particles by the iluidizinggas into the coking chambers of the battery, where carbonization of thepreheated coal is effected (United States Pat. 2,658,862), Thisprocedure is objectionable for a number of reasons, among which may bementioned that it requires the pulverizaton of the coal to reduce it toa particle size (65% minus 200 mesh) such that it can be uidized andconveyed by the uidizing gas. The coking of such tine coal results incoke of poor quality, unsatisfactory for many metallurgical uses.Because of the low bulk density of such fine coal, the charge per unitvolume of coking chamber is much lower than the charge per unit volumeof coarsely comminuted coal particles, such as are commonly used forcharging the coking chambers.

The feed of preheated coal by means of an inert gas such as coal gas, asdisclosed in my Pat. 3,047,473, leaves much to be desired from thestandpoint of effecting the charging of the coking chambers reasonablysmoothly and within a reasonable time, say not exceeding about 20minutes for each coking chamber having a capacity of about 15 to 25 tonsor more, without eX- cessive carry-over of tine coal particles in thecollector main of the oven battery and without excessive powerrequirements for the compressor or compressors required to compress theinert gas to the pressure necessary for effecting the transport of thepreheated coal particles into the `coking chambers.

The introduction of preheated coal employing a conventional larry asheretofore carried out involving the relatively rapid dumping of thecharge into the coking chamber, usually in about one or two minutes, hasthe serious objection that as the mess of hot coal enters the hot cokingchamber it may catch fire with consequent damage to the larry car. Suchrapid charging has the disadvantage of introducing excessive quantitiesof suspended particles in the gas taken olf from each coking chamber.

The problems involved in effecting feed of the preheated coal from thepreheater into the coking chambers to supply each chamber with thedesired charge of the order of 15 to 25 tons or more in the case ofmodern coke oven batteries, which may contain from 20 to 90 cokingchambers, are indeed manifold. Necessary precautions must be observed toprevent hot coal particles from catching fire. Obviously, air oroxygen-containing Ygases cannot be used as the carrier gas and henceordinary pneumatic transport employing air as the carrier gas is out ofthe question. The feed of the hot coal must (a) -be smooth and free ofinterruption into the coking chamber being charged; (b) be reasonablyrapid so that the charging can be effected within a reasonable timeperiod, permitting successive charging of the chambers after pushing thecoke therefrom to provide the empty chamber for charging; (c) be underconditions avoiding excessive carry-over of ne particles into thecollector main; (d) avoid a smoke nuisance; and (e) not interfere withthe collection of coke oven gas in the collector main from other cokingchambers at progressively different stages of coking.

It is a principal object of the present invention to provide a novelprocedure of charging the coking cham- -bers of coke oven batteries withcoarsely comminuted, preheated coal particles so as to effect suchcharging smoothly and efficiently.

The Iuse of coarsely comminuted coal, rather than fine coal permits theattainment of a satisfactory bulk density of the coke oven charge.

Other objects and advantages of this invention will be apparent from thefollowing detailed description thereof.

In accordance with this invention, coarsely comminuted coal particles,of a particle size conventionally used for charging the coking chambersof a battery and preheated to a temperature within the range of from 250to 700 F. along with a carrier gas, namely, steam or coke oven gas,preferably superheated steam, in amount to provide a relatively highweight ratio of coal to carrier gas, at least 20 to 1, are charged intoan empty coking chamber at a rate such that it takes at least about fiveminutes to introduce the entire charge into the coking chamber, which,as noted, can have a capacity of from about 15 to 25 tons or more.

The coke oven gas used as the carrier gas can be the same type of cokeoven gas as is employed in the heating flues of the battery. It issupplied to the preheated coal at ambient temperature. While coke ovengas can be used, steam is preferred for a number of reasons, including(a) steam reacts endothermically with carbon, thus reducing thetemperature conditions during the charging with consequent reduction inevolution of volatiles during the charging, and (b) steam condenses inthe hydraulic main, thus lessening the problem of maintaining properpressure in the hydraulic main during charging. The description whichfollows will, therefore, be conned chiefly to the use of steam as thecarrier gas with the understanding, however, that coke oven gas can beused instead of steam.

Desirably, before the charging of the coal-steam mixture is commenced,steam, preferably superheated steam, is introduced into the empty hotcoking chamber to provide therein a steam atmosphere. Thereafter thepreheated coarsely comminuted coal particles, along with additionalsteam at least during the initial stages of the charging, are chargedinto the steam containing coking chamber so that the weight ratio ofcoal to steam is at least 20 to l and can be from 20 to 500 to 1 in thecase of the coalsteam mixture pipe-lined into the coking chamber. As thecharging continues the amount of steam introduced with the coalparticles can be reduced and during the latter stages of charging, theamount of steam can be the minimum amount required to obtain thetransport or dow of the preheated coal. Employing mechanical transportsuch as a larry car, after introduction of about of the charge, theamount of steam introduced with the coal can be reduced to a minimum,i.e., so much so that to- Wards the end of the charging the ilow ofsteam into the coal charge fed to the coking chamber can bediscontinued.

The mixture of preheated coal and steam is introduced into the Cokingchamber to form therein the desired charge at a rate such that itrequires at least ve minutes and not more than 20 minutes, preferablyfrom 5 to 12 minutes, to introduce the entire charge into the Cokingchamber. These values are for modern coke oven batteries having cokingchambers each adapted to contain from to 25 tons of coal and avolumetric capacity of from 600 to 1200 cubic feet. Thus the rate offeed of the preheated coal is such as to require at least 0.4 minute andnot exceeding 3.3 minutes per 100 cubic feet of the volume of the cokingchamber. Stated otherwise, the rate of feed of the preheated coal issuch as to give a rise of level of coal in the coking chamber of from0.5 to 3.5 feet a minute for modern coking chambers dimensionedapproximately 40 to 45 feet long, from 12 to 18 feet high, andapproximately 11/2 feet wide.

As compared with the heretofore known and conventional practice ofcharging coking chambers employing a larry, the rate of feed of the coalinto the coking chamber by the procedure of this invention is relativelyslow. The charging time required is at least about five times that nowemployed involving the dumping of a charge from a larry through thecharging holes into the coking chamber. Attempts to introduce thepreheated coal relatively rapidly at rates corresponding to the ratesnow used for charging wet coal so that the time required for each cokingchamber is of the order of one to two minutes results in a largeevolution of gases from the mass of preheated coal thus fed into the hotcoking chamber, which gases may catch iire with objectionable smokenuisance and excessive carryover of coal particles into the collectormain of the battery. Operating, on the other hand, under the recitedconditions of relatively slow charging rate, yet not too slow to permitcharging of successive coking chambers, in a practical time cycle and inthe presence of superheated steam which, at least during the initialstages of the charging envelops the preheated coal particles introducedinto the hot colting chamber, eliminates flaming of the charge and givessatisfactory charging.

It is not fully understood why observance of the conditions of thisinvention, involving relatively slow charging so as to require at leastabout five minutes for introducing the charge into the coking chamber,and the presence of superheated steam or coke oven gas, preferablysteam, enveloping at least the preheated coal particles initiallyintroduced into the hot coking chamber with a coal to carrier gas weightratio of at least 20 to l, results in satisfactory charging of thepreheated coal. As the coal is initially introduced into the hotchamber, the coal tends to form an initial thin layer covering the hotwalls and door of the chamber. This black layer later becomes the outerportion of the mass of coke produced in the coking chamber but initiallyserves to retard the flow of heat from the hot walls of the battery intothe remainder of the charge introduced. This factor plus the relativelyslow rate of preheated coal introduction reduces the rate of volatileevolution from the preheated coal suiciently to prevent objectionableaming and permits the collector main or mains to accommodate thevolatiles evolved during the charging.

In accordance with a preferred embodiment of this invention, thepreheated coal, superheated steam mixture is fed to the coking chambersthrough a pipeline provided with branches with at least one branchleading into each coking chamber. The invention, however, is not limitedto this mode of transport of the preheated coal into the coking chamber.Other modes of effecting the feed of the preheated coal into the cokingchamber, such as larry feed with slow charging and the disclosed coal tocarrier gas weight ratio can used.

In the preferred embodiment, transporting from one to three tons ofpreheated coal per minute through a pipeline of six inch diameter, thecoal being unscreened and having a maximum particle size of about oneinch, i.e., the coal being coarsely comminuted, the coal and superheatedsteam at a pressure of from 4 to 50 p.s.i.g., preferably 5 to 30p.s.i.g., are first introduced into the upstream end of the pipeline.The pressure within the pipeline at the upstream end is from 4 to 50p.s.i.g. and the velocity of the steam, preheated coal mixture withinthe pipeline is from 10 to 200 feet per second. Steam jets for impellingand dispersing the coal are positioned in the bottom of the pipeline toproduce high velocity jets of steam at an angle of from 5 degrees to 20degrees to the horizontal and in a direction the same as the desireddirection of ow of the preheated coal through the pipeline. Steam issupplied to these jets at pressures ranging from 25 to 600 p.s.i.g.Along the length of the pipeline, at the bottom thereof, i.e., at theoutside of the pipeline on curved sections desirably having a radius ofcurvature of at least about six feet and at the true bottom on straighthorizontal runs, the spacing of these jets is from 6 inches to 36 inchesapart, preferably 12 to 18 inches apart. The jets are spaced somewhatcloser in the bends, e.g., every 5 degrees to 9 degrees of arc. At least10 jets are positioned in a degree bend having a six foot radius whichcorresponds to one jet every 12 inches, although preferred spacing isone jet every six or seven inches. A larger radius of curvature permitslarger spacing of the jets.

In each jet the steam expands to at least sonic and preferablysupersonic velocity, and thus imparts an impulse to the coal particlesin the desired direction of flow through the pipeline thus aiding theflow. In other words, the energy of the sonic or supersonic velocity ofthe jets is converted into impulses aiding the transport of the solidcoal particles from one jet to the next and thus through the pipeline.Under the conditions herein disclosed, relatively low pressureconditions are maintained throughout the pipeline within the range offrom to 50 p.s.i.g. and velocities which do not exceed about 200 feetper second. The introduction of superheated steam through jets spaced asherein disclosed avoids the necessity of excessively high pressures atthe entry to the pipeline.

I have found that the rate of flow of unscreened hammer-milled coalthrough a horizontal pipeline six inches in diameter and 130 feet long,equipped with triple holed jet plugs spaced 8 inches apart, is given bythe following empirical relationship:

R=rate of flow of coal in tons per minute P=pressure in p.s.i.g. in themeasuring bin supplying the hot coal to the feed end of the pipeline(i.e., bin 35 in FIG. 1).

Employing a relatively long pipeline, in the case of large batteries orwhere one and the same pipeline supplies more than one battery, or wherethe coal preheater is so spaced relative to the battery that a longpipeline is necessary, excess steam is bled olf from the mixture thereofwith the preheated coal particles at one or more points along the lengthof the pipeline to maintain the steam velocity in the pipeline below 200feet per second and yet permit the introduction of superheated steam ata plurality of closely spaced points along the length of the pipeline toaid the transport of the coal particles through the pipeline.Preferably, the excess steam is bled off by subjecting the mixture tocentrifugal force, for example, by flow through a curved section of thepipeline or by passing a side stream of the mixture through a cycloneseparator, to produce a body of steam substantially free of coalparticles. Steam is vented from this body thereof substantially free ofcoal particles. Where a side stream is removed, coal particles carriedthereby can be returned to the pipeline.

The venting or bleeding olf of the steam from the pipeline as hereindisclosed permits replacement thereof along the length of the pipelineby the steam introduced at sonic or supersonic velocities in the form ofjets to aid the propulsion of the coal particles through the pipeline,and this without excessive build-up of velocity of mixture of coal andsuperheated steam in the pipeline. The number of such venting unitsemployed in any pipeline will depend on the particle size of the coalparticles transported, the length of the line, the quantity of steamjetted thereinto, and the pressure in the feed tank at the head of thepipeline. For any given pipeline, it is a comparatively simple matter todetermine the number of such venting units which should be used foroptimum ow of the preheated coal particles. In general, two units shouldbe used per 100 feet of pipeline length when conveying preheatedhammer-milled coal in a pipeline having an inside diameter of six inchesemploying steam as the carrier gas supplied to the jets under a pressureof from 150 to 600 p.s.i.g., the steam jets being spaced apartapproximately inches between adjacent jets. The steam upon entering thepipeline through the jets expands to at least sonic velocity when theabsolute pressure of the steam supply is at least twice that of theabsolute pressure in the pipeline.

At least one steam venting unit should be positioned at a point wherethe pipeline communicates with the branch leading into the cokingchamber. Each branch leading into a coking chamber can itself be shapedto produce a curved bend subjecting the mixture flowing therethrough tocentrifugal force to produce in the bend a -body of steam substantiallyfree of coal particles, which body is vented either to the atmosphere orto an adjacent coking chamber or to a condenser. Thus the mixture whichis charged into the coking chambers has a high ratio of preheated coalparticles to steam. This facilitates disentrainment of the coalparticles from the steam within the coking chamber and hence minimizescarry-over of coal into the gas offtake.

Good transport through the pipeline is obtained when the ratio ofpreheated coal particles to steam on a weight basis at the inlet end ofthe pipeline, is 20 to 3501, preferably about in the pipeline, up to thedischarge point into the coking chamber, is 20 to 150, preferably about60, and upon discharge into the coking chamber is 20` to 500, preferablyabout 80.

The feature of venting the pipeline to remove excess steam to attain theaforesaid ratios and to permit the maintenance of steam velocities below200 feet per second within the pipeline is disclosed and claimed in mycopending application Ser. No. 382,609, filed July 14, 1964.

In the preferred embodiment, complete charging of the oven chamber isaccomplished by imparting to the coal, carrier gas mixture, at the pointof introducion into the coking chamber, a velocity adequate todistribute the coal throughout the length of the coking chamber.

Preferably during the charging, the pressure of the steam at thecharging inlet end of the Icoking chamber (the end of the chamber wherethe preheated coal enters) is limited to the range of 1/2 to 2 p.s.i.g.The opposite end of the coking chamber can be vented to the collectormain or to an adjacent coking chamber during the charging to insure thatthe pressure at that end is less than that on the charging end of thechamber. In the case of new batteries built to practice this invention,which can be built without charging holes in the roof and which haveonly one collector main at the opposite side of the battery from thatcontaining the coal inlets, such differential pressure can be created bynot venting the charging end of each coking chamber during the chargingand letting the pressure build up to the desired extent while theopposite end of the chamber is in communication with the collector main.Existing batteries require the sealing of the charging holes at thecharging end of the coking chambers to prevent leakage of gas throughthese charging holes which would prevent pressure build-up to within therange of from 1/2 to 2 p.s.i.g. This differential pressure within thecoking chamber during charging tends to effect the distribution of thecharge throughout the length of the chamber and gives a ycharge whichdoes not require leveling. In other words, the pressure differentialfacilitates the charging of the far end of the oven chamber withdisposition of the charge into the coking chamber throughout its lengthto a reasonably uniform height so that leveling of the charge with aleveling bar is not necessary.

In the accompanying drawings forming a part of this specification andshowing for purposes of exemplification a preferred embodiment of thisinvention without limiting the claimed invention to such illustrativeinstance:

FIG. 1 is a flow sheet, diagrammatic in character, showing a preferredlayout of equipment for supplying preheated coal to the coking chambersof a battery;

FIG. 2 is a fragmentary perspective of a coke oven battery showing thepreferred technique for transporting the preheated coal to the -cokingchambers of the battery;

FIG. 3 is a fragmentary Ivertical section through a coking chamber of anexisting battery modified for charging by the present invention;

FIG. 4 is a fragmentary vertical section through a coking chambershowing a charging larry in position to charge the coking chamber, whichlarry is designed to effect the charging in accordance with the presentinvention;

FIG. 5 is a fragmentary sectional view, on an enlarged scale as comparedwith the scale of the other gures, through a portion of the pipelineshowing one of the jet nozzles; and

FIG. 6 is a fragmentary sectional view through the pipeline, at rightangles to the section of FIG. 5 and showing a plan view of a jet nozzlein the pipeline.

Referring to FIG. 1, wet coal containing from 3% to 12% lby weight ofmoisture, usually from 7% to 8% moisture, is supplied by a conveyor 10to the coal bin 11. This wet coal is the usual hammer-milled coalemployed in charging the coking chambers of the coke oven battery, i.e.,coarsely comminuted, the particles of which are less than one inch insize in their greatest dimension and usually of a particle size suchthat from 3% to 20% 0f the particles are larger than about 1A inch; from8% to 40% of the particles are larger than 1/s inch; and over 50% of theparticles are larger than 0.04 inch. In the trade this size of coal isreferred to as 60% to 90% through a 1A; inch screen. It is the particlesize commonly used for charging the coking chambers of a battery toproduce metallurgical coke. Coals of such particle size are referred toherein as coarsely comminuted coal.

In the embodiment of the invention shown in FIG. 1, a preheatinginstallation is shown involving two preheaters, each with associateddust collectors. The number of preheaters used will, of course, dependon the capacity of the preheater as well as that of the coking chambers.For smaller installations where one preheater will produce preheatedcoal at a temperature Within the range of from 250 to 700 F. insul'licient quantity to supply the coking chambers of the battery, thenthe installation need have only one such preheater or, if desired, asecond as a standby unit. Larger installations will, of course, havemore than one coal preheating unit.

Since both preheating units 12 of FIG. 1 are the same, only one will bedescribed in detail. Each unit comprises a heater 13, desirably in theform of the well-known Herreschot furnace, comprising a series ofsuperimposed hearths 14 over which rabble arms 15 rotate to effect thedischarge of the coal from an upper hearth to a lower hearth. Hotcombustion gases produced in the combustion chamber 16 supplied withfuel through line 17 and air through line 18 to support combustion enterthe base of the heater 14 and flow upwardly countercurrent to thedescending coal. The heaters 13 can be of any known type in whicheffective preheating of the coal is effected to a temperature within therange of from 250 to 700 F.; the Herreschoff type represents one suchheater.

The preheated coal at a temperature within the range of from 250 to 700F. is withdrawn from the base of the heater through line 21 which entersthe top of receiving bin 22. Hot combustion gases leaving the heaterexit through line 23 into a cyclone separator 24, desirably a dual unitof known type. Coal entrained in the hot gases settle out in thiscyclone separator 24 and is discharged through valve controlled line 25into the hot coal line 21.

Exhaust gas from the cyclone separator 24 is pumped through line 26 intoa dust collector 27 which can be of the cyclone separator type. In dustcollector 27 solid particles are separated and are discharged throughvalve controlled line 29 into the coal feed line 21. The substantiallydust-free gas can be discharged into the atmosphere through line 31.

C1 is a `control of known type which controls the amount of fuelsupplied through line 17 responsive to the temperature of the preheatedcoal to maintain the temperature of the latter substantially constant,C2 is a control of known type which controls the volume of exhaust gasrecycled through line 26 to the combustion chamber 16 where this exhaustgas mixes wth the combustion products and thus tempers the temperatureof the combustion gases supplied to the heater 13 and maintains thetemperature of the combustion gases at the desired value. Each heater isequipped with an oxygen analyzer unit of known type to insure that thecombustion gases entering the heater are free of oxygen. The preheaterscan be supplied with additional conventional temperature and pressurecontrollers and electrical interlocks to insure proper sequence ofoperation under selected conditions of temperature and pressure foroptimum performance of the preheating equipment.

Receiving bin 22 discharges the preheated coal to an elevating conveyor32 which delivers the preheated coal into a measuring bin 35. Measuringbin 35 is of suicient capacity to maintain therein preheated coal inamount to supply the desired complete charge for charging an emptycoking chamber. Measuring bin 35 is periodically lled from the receivingbin 22 which has an apppreciably larger capacity than the measuring bin35. In storage or receiving bin`22 is stored enough of the preheatedcoal to insure smooth operation, i.e., to supply the measuring bin 35 atintervals depending upon the charging cycle with the correct amount ofpreheated coal to supply the desired charge to the coking chamber beingcharged. When this amount of coal is introduced into the measuring bin35, the valve 34 is closed to seal the measuring bin. Steam is thenintroduced into the measuring bin through line S (FIG. 2), having avalve S1 therein, to produce a mixture of steam and coal particles whichwill flow readily, e.g., a mixture under a pressure of from 4 to 50p.s.i.g.

Measuring bin 35 has at its discharge end a crusher 36 which can be ofany desired type, such, for example, as the crusher disclosed in myco-pending application Ser. No. 282,351 led May 22, 1963, now abandoned,in favor of my continuation application therefrom, Ser. No. 588,217, ledMar. 19, 1968, now Patent 3,374,151. The crusher when used, has thefunction of crushing any oversized particles or agglomerates, thusinsuring the delivery to the accelerator chamber 37 of coal welldispersed in the carrier gas having a maximum particle size conducive totrouble-free transport through the pipeline into the coking chambers.

In the embodiment shown in FIG. 2, the crusher cornprises one set ofcrushing arms 41 each mounted for rotation on shaft 42 and cooperatingwith a second set of crusher arms 43 mounted for rotation on shaft 44.The arms 41 and 43 are arranged to rotate in interengagement relation asindicated diagrammatically in FIG. 2 so as to agitate the hot coal andcrush oversize lumps. A valve 45 is mounted just above the crusher 36and controls the ow of hot coal and steam from measuring bin 35 into thecrusher 36.

As shown in FIG. 2, the accelerator chamber 37 is of truncated conicalshape and has a steam jet 52 near the lower end thereof. The base ofthis chamber where it joins the inlet end of the pipeline 38 is of thesame diameter as this inlet end. 'The joint between the two is such thatstreamline ow takes place from the exit of the accelerator chamber 37into the pipeline 38. This joint is free of any obstructions to iiowtherethrough. The length of the portion of the accelerator chamber 37from the exit of the Crusher to the discharge end of this chamber is atleast suicient to permit accelerative fall of the mixture of coalparticles and steam from the crusher 36 into the inlet end of thepipeline without any tendency for accumulation or packing of the coalparticles to take place in the accelerator chamber. This is importantbecause by having this distance so dimensioned, accumulation of coalparticles in the lower end of the accelerator chamber, which ifpermitted to develop would tend to obstruct or clog the iiow into thepipeline, is prevented. Acceleration of the coal in a gravity typeaccelerator has been shown in the drawing and described above. However,other types of accelerators can be used, such, for example, as the knownmechanical slingers.

The dimensions of the accelerator chamber as well as of the pipeline,the drier and associated equipment will, of course, vary for eachinstallation and in general depend on the capacity of the cokingchambers, the charging cycle used and the size of the coal particlescharged.

In the embodiment of the invention shown in FIGS. 2 and 3, pipeline 38has an inside diameter of from 4 to 8 inches, preferably about 6 inches,and leads from the exit end of the accelerator chamber 37 to a manifold47 which extends along the length of the battery. Manifold 47 has adischarge conduit or branch 48 individual to each coking chamber leadinginto one end of that coking chamber, preferably at an angle of less thanabout 23 degrees to the horizontal so that the coal-steam mixture isdischarged into one end of the coking chamber and ows therefrom towardthe opposite end of the coking chamber, disentrainment of the coal fromthe steam taking place as the coal is fed into the coking chamber.

As customary, the coking chambers, a section through one of which isshown in FIG. 3, are each provided with doors 49 at the opposite ends.The usual gas off-take 50 leads into a collector main M (FIG. 4) fromthe opposite end of the coking chamber from that into which thecoalsuperheated steam mixture is introduced. Existing batteries to whichthis invention may be applied customarily have charging holes H in theroof thereof which are equipped with the usual charging hole covers H'(FIG. 3).

Pipeline 38, manifold 47 and each branch 48 are each provided, at aplurality of closely spaced points along their lengths, with jet plugs52 for introducing superheated steam. These jet plugs 52 arecommunicably connected With a steam line 53 through branches '54 eachequipped with a valve 55. Steam line 53 is positioned adjacent pipeline38, manifold 47 and each branch 48 to supply them With steam under apressure of from 25 to 60() p.s.i.g. through the jet plugs 52 spaced ashereinabove disclosed. The steam is jetted into the line in thedirection of flow therethrough. For example, in the case of the pipeline38, as shown in FIG. 5, in which the arrow 56 indicates the direction offlow through the pipeline, and arrows 57 the direction of steam jet llowinto the pipeline, the steam enters at sonic or supersonic velocitiesand imparts impulses to the owing mixture, aiding the flow through thepipeline; thus the sonic or supersonic velocity of the steam at thepoint of entry is immediately transformed into the energy imparted tothe hot coal-superheated steam mixture to aid flow from one jet to thenext. The pressure within the pipeline 38 and manifold 47 remains withinthe range of from 0 to 50 p.s.i.g. and the velocity of the coal-steammixture below 200 feet per second.

The valves 55 in branches 54 can be adjusted to give the desired sonicor supersonic velocity of flow into the pipeline or can be closed whenit is desired to reduce the number of branches supplying fresh steam tothe pipeline.

A preferred form of jet plug 52 is shown in FIGS. and 6 and comprises ahexagonal plug 61 having a threaded end 62 in threaded engagement withina bore 63 in the wall of the pipeline 38 or manifold 47. The top ofthreaded end 62 lies flush with the inner wall of the pipeline toprovide a smooth interior where the jets enter the pipeline or manifoldfree of obstruction to the ow of the steam-coal mixture and also free ofpockets or dead spaces. Plug 61 has a nozzle 64 or a group of suchnozzles 64, each of venturi shape having a divergent or exit portion 65,the included angle formed by the walls of which is between 5 and 7degrees and having an entrance portion that is elfectively convergent.In the embodiment shown in FIGS. 5 and 6, each plug 52 has three suchnozzles communicating with a passage 67 leading into a central bore 68in plug 61. Preferably each nozzle delivers a jet of super-heated steamat an angle of about 5 to Z0 degrees with respect to the axis of thepipeline at the point where the jet nozzle is positioned, e.g., in thecase of a straightaway or horizontal pipeline, at an angle of about 5 to20 degrees with respect to the horizontal. The end 69 of each plug 52 isthreaded at 71 to receive the threaded end 72 of a branch 54 leadingfrom the steam line. This arrangement provides fan-like jets of steamimparting velocity or impulses to the owing mixture of preheated coaland superheated steam in the direction of ow indicated by the arrow l56(FIG. 5).

The manifold 47 extends the full length of the battery, along one sidethereof, desirably the side opposite to that on which the collector mainis positioned. Each branch 48 leading from the manifold 47 is individualto a coking chamber 75 of the battery. Each branch 48 is of arced orcurved shape; the radius of curvature is preferably about six feet. Theexit end 76 of the branch extends into the refractory roof of thebattery and leads into a downwardly inclined passageway 77 (FIG. 3) inopen communication with a coking chamber 75. The angle of inclination tothe horizontal of the exit end 76 and the passageway 77 is such as todirect a flowing stream of superheated steam and preheated coarselycomminuted coal particles in a downwardly inclined direction toward theopposite end of the coking chamber. An angle less than about 23 degreesto the horizontal (i.e., the angle formed between the axis of thepassageway 77 and the horizontal) gives satisfactory charging. While inPIG. 3 the passageway 77 is shown leading into the lower end 78 of acharging hole H, the passageway 77 need not communicate with a charginghole. FIG. 3 shows a construction applied to an existing oven batteryhaving charging holes H, three in number, speed across the top of eachcoking chamber. In the case of new batteries, to which this invention isapplied, the roofs of the coking chambers need not have any chargingholes therein.

As noted, each branch 48 has a plurality of closely spaced steam jetplugs 52 therein. The spacing of the jets is the same as in a curvedsection of the pipeline. For the sake of clarity of illustration, all ofthe jets in the pipeline 38, manifold 47, and each branch 48, have notbeen shown on the drawing.

Flow through each branch 48 from the manifold 47 is controlled by a pairof valves 81 and 81. Valves 81 are positioned in the manifold 47 andcontrol ow through this manifold to the branch 48 leading into thecoking chamber to be charged. Thus all valves 81 in the portion ofmanifold 47 leading up to the branch 48 communicating with the cokingchamber to be charged are open and at least the valve 81 in the manifold47 immediately following the branch leading into the coking chamber tobe charged is closed. Thus the coal-superheated steam mixture must flowinto the branch communicating with the coking chamber to be charged.Each branch 48 has a valve 81 at the inlet end thereof which controlsthe flow' from manifold 47 thereinto. Each valve 81 and 81' is equippedwith a pressure uid cylinder 82 for egecting actuation thereof. Valves81 and 81 controlling flow into a coking chamber to be charged areopened when that coking chamber is empty and in condition for charging;these valves are closed when the charge has been introduced into thatchamber. Valves 81 and 81' of the respective branches 48 and the rest ofthe equipment can be operated through suitable timing mechanism so thatautomatic introduction takes place of superheated steam into thesuccessive empty hot chambers, followed by the feed thereinto ofpreheated coal-steam mixture, as well as the feed of the preheated coalinto the measuring bin 3S from the receiving bin 22 and into the latterfrom the preheater 12.

Preferably, but not necessarily, each branch 48 is equipped with ableed-off 83 leading from the inner curved portion 84 of the branch intoan adjoining coking chamber 75, i.e., the bleed-off leads into a cokingchamber adjoining the chamber receiving the charge. As the mixture ofsuperheated steam and preheated coal ows through the curved portion 84,it is subjected to centrifugal force so that substantially all of thecoal particles tend to concentrate in the locality of the outer wall ofthe curved portion 84, i.e., the wall remote from the port or openingleading into the bleed-olf 83. Hence in the vicinity of the inlet to thebleed-olf 83, the superheated steam is substantially free of coalparticles. This superhetaed steam ilows through the bleed-olf 83 intothe adjoining chamber which is in an advanced stage of the coking andhence can readily accommodate the carrier gas which flows from thatcoking chamber into the collector main.

The bleed-ofi of superheated steam from the coal-steam mixture flowinginto the coking chamber being charged increases the coal to steam weightratio of the mixture charged into the steam-containing coldng chamber.This facilitates disentrainment of the coal from the steam. The steamentering the chamber being charged upon disentrainment from the coalparticles exists through the uptake leading into the collector main. Thesteam entering the adjacent chamber or a pair of chambers on theopposite sides of the coking chamber being charged, if desired, owsacross the open space above the coke in these chambers and exits fromthese chambers through the gas off-takes into the collector main. Anysolid coal particles therein, for the most part, settle out and becomepart of the coke charge in the adjacent chambers.

In operation, after the preheated coal is introduced into the measuringbin 35 in amount to supply a charge for a coking chamber, valve 34 isclosed. Valve 45 had been closed previously. The valves 81 and 81controlling ow to the branch leading to the cokng chamber to be chargedare opened while closing the valves 81 in the coal manifold downstreamof the coking chamber being charged. Steam is turned on to the jetsupstream of this coking chamber. The crusher is actuated; valve 4S isopened and steam is supplied, preferably, to the lower part of bin 35 traise it to desired pressure, eg., 4 to 50 p.s.i.g. The steam jetsupstream of the coking chamber being charged serve to produce a steamatmosphere in the coking chamber to be charged. The formation of suchsteam atmosphere in each coking chamber before introduction of the hotcoal charge thereinto represents preferred operation, althoughsatisfactory charging can be effected by not tilling the coking chamberto be chargged with steam prior to the commencement of the feed of thecoal-steam mixture into that coking chamber. Thereafter coal flow to theoven begins and continues at a rate to introduce the charge in from about5 to 12 minutes.

In the case of a long pipeline, say exceeding 100 feet in length, theline is provided with a curved portion 91 which can be in the form of ahorizontal curve, Le., lie in a horizontal plane as shown in FIG. 2, ora vertical curve, i.e., lie in a vertical plane, as more fully describedin my copending application Ser. No. 382,609 tiled July 14, 1964. Thiscurved portion 91 desirably is made up of successive curved sections A,B and C designed for streamline flow therethrough. The radii ofcurvature of adjacent portions A and B, and B and C are diametricallyopposite each other. For a six-inch pipeline the radius of curvature ispreferably about six feet. As the mixture of preheated coal andsuperheated steam iiows through the curved portion 91, it is subjectedto centrifugal force causing the coal particles to concentrate in thelocality of portion 92 and forming opposite this locality at 93 a bodyof steam substantially free of coal particles. A bleed-off or vent 94 isprovided for bleeding oif steam from this body, thus removing enough ofthe superheated steam to avoid excessive velocities in the pipeline andto enable the introduction of superheated steam through the subsequentjets in the direction of flow of the superheated steam-preheated coalmixture without creating excessive velocities within the pipeline, themanifold 47 and the branch 48 leading from the manifold into the cokingchamber to be charged.

After initiation of the introduction of the mixture of preheated coaland superheated steam into the coking chambers, the pressure of thesteam released from the mixture can be permitted to build up in the endof the coking chamber Where the mixture is introduced. That is to saythis end of the coking chamber is not vented. In the case of an existingbattery having charging holes, modified to practice this invention,precautions are taken to insure that the charging hole covers at the endof the coking chamber which receives the charge are tightly sealed toenable the pressure in that end of the chamber to build up to within therange of from 1/2 to 2 p.s.i.g. The opposite end of the coking chambercommunicating with the usual gas oH-take at the opposite end of thecoking chamber is thus at a lower pressure. This opposite end of thecoking chamber is usually vented through the olf-take to the collectormain during the charging. The differential pressure thus created betweenthe respective ends of each chamber during the charging thereoffacilitates the ow of the coal-steam mixture from the end of the chamberwhere it is introduced to the opposite end and gives a distribution ofthe coal within the coking chamber so as to produce a reasonably uniformlevel of coal throughout the length of the coking chamber, i.e., adisposition of the charge requiring no leveling. Hence while the presentinvention is not confined to charging without leveling, it enables suchcharging to be effected.

When the measured charge has been delivered from the measuring bin 35,valve 45 is closed. When this charge has been introduced into thechamber being charged, the steam jets 52 are turned off and theoperation of the crusher 36 interrupted. Valve 34 is then opened and afresh charge of preheated coal introduced from the receiving bin 22 intothe measuring bin 35. Once this charge has been introduced intomeasuring bin 35, the operation hereinabove described is repeated forthe next coking chamber to be charged.

During the charging of each chamber, in the embodiment shown in FIG. 2,branch 48 is vented into an adjacent coking chamber through bleed-oit83, thus reducing the steam input into the chamber being charged, i.e.,increasing the weight ratio of coal to steam introduced into the cokingchamber being charged. Higher coal to steam ratios facilitatedisentrainment of the coal from the steam and tends to reduce thecharging time. It also tends to prevent carry-over of ne coal particlesby the steam introduced into the chamber being charged from that chamberinto the collector main. Bleed-off 83 can be provided with a valve tocontrol ow therethrough or to permit optional use of this bleed-off.

Bleed-off 83 can be designed to connect with two adjoining cokingchambers to vent steam into these two chambers. Operating in this mannerfacilitates recovery of coal particles carried by the steam thus ventedinto the adjacent chambers, which lcoal particles form part of the coalcharge in these adjacent chambers and are eventually converted to coke.

With relatively high coal to steam ratios, the venting of the steam-coalmixture introduced through branch 48 into the chamber being charged canbe eliminated entirely. As a general rule, venting into one adjacentcoking chamber is useful in minimizing carry-over of coal particles bythe steam from the chamber being charged into the collector main andalso in facilitating dissentrainment of the coal from the steam in thechamber being charged in that it reduces the amount of steam introducedinto the chamber being charged.

The following example of charging a coke oven battery, the cokingchambers of which are approximately 12 feet high, 40 feet long and 18inches Wide, is given for illustrative purposes. The equipment used issubstantially that shown in FIG. 2. The measuring bin 35 afterintroduction of the charge of preheated coal (15 tons) at a temperatureof about 650 F. was pressurized with superheated steam to a pressure of9.8 p.s.i.g. The crusher 36 Was driven at approximately 93 r.p.m. Steamwas introduced into the coking chamber to form therein a steamatmosphere. Steam was then introduced through the jets spaced along thelength of the pipeline 8 inches apart in the horizontal stretch andsomewhat closer in the bends of the pipeline. The total conveying steamused was 506 pounds equivalent to 79 pounds per minute` The steampressure was 287 psig.; on the average 65.6 pounds per minute of steamwas supplied to the jets in the pipeline.

The charging of the chamber required 6.4 minutes. At

l3 the end of this time the coal was disposed in the chamber in a moundwith the level of the coal at the ends of the chamber about a foot belowthe level in the middle of the chamber. Upon leveling the coal wasdisposed at a substantially uniform height throughout the length of thechamber. The chamber which as noted was 12 feet high was lled to aheight of 11.2 feet.

Such charging is repeated for each chamber of the battery bymanipulation of the valves.

In the battery of FIG. 4, a charging larry 100, having three charginghoppers 101. one for each charging hole travels on rails 102 on the roofof the battery. Each of the hoppers has a covered top which preventsaccess of air to the hot coal in the hopper. The cover, of course, canbe removed to permit lling the hopper with hot coal. This larry 100 canbe of a known type involving a rotary discharge plate 103 at the base ofeach charging hopper 101. Each plate 103 is rotated by a motor drive(not shown) as conventional, the speed of which is adjustable to givedischarge of coal at the desired rate. Each discharge plate delivers thecoal to a discharge chute which, as conventional, communicates with adrop sleeve 104. These sleeves in their lowered position bridge thespaces between the discharge ends of the discharge chutes and the inletends of the charging holes communicating therewith. Larry 100 travelsalong the top of the battery, receives a charge of preheated coarselycomminuted coal, preheated to a temperature within the range of from 250to 700 F. at the loading station for the larry and then is moved intocharging position over the empty chamber to be charged.

Positioned at one side of the battery running the length thereof is asteam line 105. This line has branches 106, one individual to eachcoking chamber provided with a valve 107 to control ow therethrough andequipped with a conventional quick attachable and detachable coupling108 for connection to flexible steam conduit 109 carried by the larry.Conduit 109 communicates with a steam line 110 having three branches111, one for each charging hopper 101. Each branch 111 has a exiblelower end 112 which leads into a drop sleeve -104 as shown in FIG. 4.Conduit 109 has a ow control valve 115 therein.

When the larry is spotted over the empty chamber to be charged, conduit109 is coupled to steam line 105. Valves 107 and 115 individual to thechamber being charged are turned on to ll the chamber with superheatedsteam. The steam flow is continued during the charging which is carriedout at a rate such that from to 12 minutes are required to introduce thecharge into the coking chamber; such charging is effected by rotatingthe discharge plates 103 at a rate to give the necessary slower .feed ofthe hot coal through the drop sleeves into the coking chamber. The flowof steam into the coal passing through the drop sleeve preventsaspiration of air into the falling coal stream and thus avoids tires andexplosion hazards which would be involved in charging hot coal from alarry into a hot coking chamber by dumping same from the larry into thecoking chamber at the relatively rapid rates normally used. The steam,with the slow charging as hereinabove described, thus serves a dualpurpose. Its presence in the coking chamber when hot coal first entersprotects the dry hot coal from excessively fast carbonization which,were it to occur, would result in excessive evolution of volatiles whichcarry tine coal particles up through the gas off-take; also, the steamblankets the falling coal from the air thus avoiding tires andexplosions.

The amount of steam introduced should be as hereinabove described toprovide a relatively high coal to steam weight ratio, so that rapiddisentrainment of the coal from the steam takes place in the cokingchamber. The coal to steam weight ratio can be from 20 or more to 1.Coke oven gas can be used instead of steam, supplied to the larry'from acoke oven gas main at ambient temperature, in amount such as to provideabout the same weight ratio as in the case of steam.

While preferred embodiments have been disclosed hereinvand illustratedin the drawings, it will be understood this invention is not limited tothis disclosure including the showing of the drawings because manyvariations and otherl modifications will occur to those skilled intheart.

What is claimed is:

"1. A method of charging the coking chambers of a coke oven batteryequipped with a larry car having charging hoppers, one for each charginghole in each coking chamberof the battery, the larry car having dropsleeves, one for each charging hopper, which sleeve, when the larry is"spotted in charging position is lowered to place the discharge outletof the charging hopper with which the sleeve is associated incommunication with the charging hole bridging the space between saiddischarge outlet and said charging hole, which method comprisespreheating the coal particles in coarsely comminuted condition to atemperature within the range of from 250 to 700 F., feeding thepreheated coal into the charging hoppers of the larry `in an amountequal to a desired charge for a coking chamber, moving the larrycontaining the charge of preheated coal into position to charge a cokingchamber to be charged, discharging the preheated coal from the charginghoppers of the larry through the drop sleeves into the coking chamber tobe charged at a rate to produce the desired charge within said cokingchamber in not less than about 5 minutes while introducing a carrier gasfrom the group consisting of steam and coke oven gas into the dropsleeves to prevent aspiration of air into the coal streams fallingthrough said drop sleeves into the coking chambers.

2. The method of charging the coking chambers of a coke oven battery asdened in claim 1, in which steam is introduced into the drop sleevesduring at least the initial portion of the discharge of the preheatedcoal therethrough into the coking chamber and the rate of discharge ofthe preheated coal from the charging hoppers of the larry into thecoking chamber is such as to till each cubic feet of volume of thecoking chamber in from 0.4 to 3.3 minutes.

References Cited UNITED STATES PATENTS 2,488,952 11/ 1949 Wilpoutte etal. 202-262 3,047,473 7/1962 Schmidt 201-31 WILBUR L. BASCOMB, JR.,Primary Examiner D. EDWARDS, Assistant Examiner U.S. Cl. X.R. 20Z-262;214-18

